Microfiche duplicating apparatus, wherein an unlimited number of duplicates of microfiche masters can be produced by means of contact printing, is well known in the art. One such apparatus is disclosed in U.S. Pat. No. 3,756,708.
As shown therein, the apparatus comprises a developer station including a pressure pad suspended within a frame and connected thereto by toggle linkage which actuates the developer pad -upward and downward within the developer station. The developer pad is provided with a plurality of bores which pass from edge to edge thereof, and a face of the developer pad is provided with a plurality of holes connecting the face with the bores. The linkage, when actuated, exerts a substantial force on the developer pad to press the pad tightly against a developer chamber so that the chamber will be sealed against a high pressure anhydrous ammonia used for the development of the diazo type films. When the pad face presses against the film, any entrapped air escapes through the holes and into the bores.
Although the foregoing has met with a considerable amount of success; it does not provide means for cleaning or purging the developer chamber of condensed moisture and residual ammonia after each development cycle thereby resulting in film spotting due to moisture and discoloration of the film due to pre-development. Also, there are no provisions in the device of the above patent for eliminating the undesirable ammonia smell.